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V-5 Compressor:

DESCRIPTION
The Variable Displacement Orifice Tube (VDOT) refrigerant system employs the constant run V-5 compressor The V-5 is a variable displacement compressor that can match the air conditioning demand under all conditions without cycling. The basic compressor mechanism is a variable angle wobble-plate with 5 axially oriented cylinders. The Center of control of the compressor displacement is a bellows actuated control valve located in the rear head of the compressor that senses compressor suction pressure. The wobble-plate angle and compressor displacement are controlled by the crankcase suction pressure differential. When the A/C capacity demand is high, the suction pressure will be above the control point and the valve will maintain a bleed from crankcase to suction; when no crankcase suction pressure differential exists the compressor will have maximum displacement.

OPERATION
When the A/C capacity demand is lower and the suction pressure reaches the control point, the valve will bleed discharge gas into the crankcase and close off a passage from the crankcase to the suction plenum. The angle of the wobble-plate is controlled by a force balance on the 5 pistons. A slight elevation of the crankcase suction pressure differential creates a total force on the pistons resulting in a movement about the wobble-plate pivot pin that reduces the plate angle.

When the engine is turned OFF with the A/C system operating, the refrigerant in the system will flow from the high-pressure side of the orifice tube to the low-pressure side until the pressure is equalized. This may be detected as a faint sound of liquid flowing (hissing) for 30 to 60 seconds and is a normal condition.